Phosphorous-containing benzothiophenes

ABSTRACT

This invention relates to the fields of pharmaceutical and organic chemistry and provides novel phosphorous-containing benzothiophene compounds which are useful for the treatment of the various medical indications associated with post-menopausal syndrome, as well as estrogen dependent diseases including cancer of the breast, uterus and cervix. The present invention further relates to intermediate compounds and processes useful for preparing the pharmaceutically active compounds of the present invention, and pharmaceutical compositions.

FIELD OF THE INVENTION

This invention relates to the fields of pharmaceutical and organic chemistry and provides novel phosphorous-containing benzothiophene compounds which are useful for the treatment of the various medical indications associated with post-menopausal syndrome, as well as estrogen dependent diseases including cancer of the breast, uterus and cervix. The present invention further relates to intermediate compounds and processes useful for preparing the pharmaceutically active compounds of the present invention, and pharmaceutical compositions.

BACKGROUND OF THE INVENTION

“Post-menopausal syndrome” is a term used to describe various pathological conditions which frequently affect women who have entered into or completed the physiological metamorphosis known as menopause. Although numerous pathologies are contemplated by the use of this term, three major effects of post-menopausal syndrome are the source of the greatest long-term medical concern: osteoporosis, cardiovascular effects such as hyperlipidemia, and estrogen-dependent cancer, particularly breast and uterine cancer.

Osteoporosis describes a group of diseases which arise from diverse etiologies, but which are characterized by the net loss of bone mass per unit volume. The consequence of this loss of bone mass and resulting bone fracture is the failure of the skeleton to provide adequate structural support for the body. One of the most common types of osteoporosis is that associated with menopause. Most women lose from about 20% to about 60% of the bone mass in the trabecular compartment of the bone within 3 to 6 years after the cessation of mensus. This rapid loss is generally associated with an increase of bone resorption and formation. However, the resorptive cycle is more dominant and the result is a net loss of bone mass. Osteoporosis is a common and serious disease among post-menopausal women.

There are an estimated 25 million women in the United States, alone, who are afflicted with this disease. The results of osteoporosis are personally harmful and also account for a large economic loss due its chronicity and the need for extensive and long term support (hospitalization and nursing home care) from the disease sequelae. This is especially true in more elderly patients. Additionally, although osteoporosis is not generally thought of as a life threatening condition, a 20% to 30% mortality rate is related with hip fractures in elderly women. A large percentage of this mortality rate can be directly associated with post-menopausal osteoporosis.

The most vulnerable tissue in the bone to the effects of post-menopausal osteoporosis is the trabecular bone. This tissue is often referred to as spongy or cancellous bone and is particularly concentrated near the ends of the bone (near the joints) and in the vertebrae of the spine. The trabecular tissue is characterized by small osteoid structures which inter-connect with each other, as well as the more solid and dense cortical tissue which makes up the outer surface and central shaft of the bone. This inter-connected network of trabeculae gives lateral support to the outer cortical structure and is critical to the bio-mechanical strength of the overall structure. In post-menopausal osteoporosis, it is, primarily, the net resorption and loss of the trabeculae which leads to the failure and fracture of bone. In light of the loss of the trabeculae in post-menopausal women, it is not surprising that the most common fractures are those associated with bones which are highly dependent on trabecular support, e.g., the vertebrae, the neck of the weight bearing bones such as the femur and the fore-arm. Indeed, hip fracture, collies fractures, and vertebral crush fractures are hall-marks of post-menopausal osteoporosis.

At this time, the only generally accepted method for treatment of post-menopausal osteoporosis is estrogen replacement therapy. Although therapy is generally successful, patient compliance with the therapy is low primarily because estrogen treatment frequently produces undesirable side effects.

Throughout premenopausal time, most women have less incidence of cardiovascular disease than age-matched men. Following menopause, however, the rate of cardiovascular disease in women slowly increases to match the rate seen in men. This loss of protection has been linked to the loss of estrogen and, in particular, to the loss of estrogen's ability to regulate the levels of serum lipids. The nature of estrogen's ability to regulate serum lipids is not well understood, but evidence to date indicates that estrogen can upregulate the low density lipid (LDL) receptors in the liver to remove excess cholesterol. Additionally, estrogen appears to have some effect on the biosynthesis of cholesterol, and other beneficial effects on cardiovascular health.

It has been reported in the literature that post-menopausal women having estrogen replacement therapy have a return of serum lipid levels to concentrations to those of the pre-menopausal state. Thus, estrogen would appear to be a reasonable treatment for this condition. However, the side-effects of estrogen replacement therapy are not acceptable to many women, thus limiting the use of this therapy. An ideal therapy for this condition would be an agent which would regulate the serum lipid level as does estrogen, but would be devoid of the side-effects and risks associated with estrogen therapy.

The third major pathology associated with post-menopausal syndrome is estrogen-dependent breast cancer and, to a lesser extent, estrogen-dependent cancers of other organs, particularly the uterus. Although such neoplasms are not solely limited to a post-menopausal women, they are more prevalent in the older, post-menopausal population. Current chemotherapy of these cancers has relied heavily on the use of anti-estrogen compounds such as, for example, tamoxifen. Although such mixed agonist-antagonists have beneficial effects in the treatment of these cancers, and the estrogenic side-effects are tolerable in acute life-threatening situations, they are not ideal. For example, these agents may have stimulatory effects on certain cancer cell populations in the uterus due to their estrogenic (agonist) properties and they may, therefore, be contraproductive in some cases. A better therapy for the treatment of these cancers would be an agent which is an anti-estrogen compound having negligible or no estrogen agonist properties on reproductive tissues.

In response to the clear need for new pharmaceutical agents which are capable of alleviating the symptoms of, inter alia, post-menopausal syndrome, the present invention provides new compounds, pharmaceutical compositions thereof, and methods of using such compounds for the treatment of post-menopausal syndrome and other estrogen-related pathological conditions such as those mentioned below.

Uterine fibrosis (uterine fibroid disease) is an old and ever present clinical problem which goes under a variety of names, including uterine fibroid disease, uterine hypertrophy, uterine lieomyomata, myometrial hypertrophy, fibrosis uteri, and fibrotic metritis. Essentially, uterine fibrosis is a condition where there is an inappropriate deposition of fibroid tissue on the wall of the uterus.

This condition is a cause of dysmenorrhea and infertility in women. The exact cause of this condition is poorly understood but evidence suggests that it is an inappropriate response of fibroid tissue to estrogen. Such a condition has been produced in rabbits by daily administrations of estrogen for 3 months. In guinea pigs, the condition has been produced by daily administration of estrogen for four months. Further, in rats, estrogen causes similar hypertrophy.

The most common treatment of uterine fibrosis involves surgical procedures both costly and sometimes a source of complications such as the formation of abdominal adhesions and infections. In some patients, initial surgery is only a temporary treatment and the fibroids regrow. In those cases a hysterectomy is performed which effectively ends the fibroids but also the reproductive life of the patient. Also, gonadotropin releasing hormone antagonists may be administered, yet their use is tempered by the fact they can lead to osteoporosis. Thus, there exists a need for new methods for treating uterine fibrosis, and the methods of the present invention satisfy that need.

Endometriosis is a condition of severe dysmenorrhea, which is accompanied by severe pain, bleeding into the endometrial masses or peritoneal cavity and often leads to infertility. The cause of the symptoms of this condition appear to be ectopic endometrial growths which respond inappropriately to normal hormonal control and are located in inappropriate tissues. Because of the inappropriate locations for endometrial growth, the tissue seems to initiate local inflammatory-like responses causing macrophage infiltration and a cascade of events leading to initiation of the painful response. The exact etiology of this disease is not well understood and its treatment by hormonal therapy is diverse, poorly defined, and marked by numerous unwanted and perhaps dangerous side effects.

One of the treatments for this disease is the use of low dose estrogen to suppress endometrial growth through a negative feedback effect on central gonadotropin release and subsequent ovarian production of estrogen; however, it is sometimes necessary to use continuous estrogen to control the symptoms. This use of estrogen can often lead to undesirable side effects and even the risk of endometrial cancer.

Another treatment consists of continuous administration of progestins which induces amenorrhea and by suppressing ovarian estrogen production can cause regressions of the endometrial growths. The use of chronic progestin therapy is often accompanied by the unpleasant CNS side effects of progestins and often leads to infertility due to suppression of ovarian function.

A third treatment consists of the administration of weak androgens, which are effective in controlling the endometriosis; however, they induce severe masculinizing effects. Several of these treatments for endometriosis have also been implicated in causing a mild degree of bone loss with continued therapy. Therefore, new methods of treating endometriosis are desirable.

Smooth aortal muscle cell proliferation plays an important role in diseases such as atherosclerosis and restenosis. Vascular restenosis after percutaneous transluminal coronary angioplasty (PTCA) has been shown to be a tissue response characterized by an early and late phase. The early phase occurring hours to days after PTCA is due to thrombosis with some vasospasms while the late phase appears to be dominated by excessive proliferation and migration of aortal smooth muscle cells. In this disease, the increased cell motility and colonization by such muscle cells and macrophages contribute significantly to the pathogenesis of the disease. The excessive proliferation and migration of vascular aortal smooth muscle cells may be the primary mechanism to the reocclusion of coronary arteries following PTCA, atherectomy, laser angioplasty and arterial bypass graft surgery. See “Intimal Proliferation of Smooth Muscle Cells as an Explanation for Recurrent Coronary Artery Stenosis after Percutaneous Transluminal Coronary Angioplasty,” Austin et al., Journal of the American College of Cardiology, 8: 369-375 (August 1985).

Vascular restenosis remains a major long term complication following surgical intervention of blocked arteries by percutaneous transluminal coronary angioplasty (PTCA), atherectomy, laser angioplasty and arterial bypass graft surgery. In about 35% of the patients who undergo PTCA, reocclusion occurs within three to six months after the procedure. The current strategies for treating vascular restenosis include mechanical intervention by devices such as stents or pharmacologic therapies including heparin, low molecular weight heparin, coumarin, aspirin, fish oil, calcium antagonist, steroids, and prostacyclin. These strategies have failed to curb the reocclusion rate and have been ineffective for the treatment and prevention of vascular restenosis. See “Prevention of Restenosis after Percutaneous Transluminal Coronary Angioplasty: The Search for a ‘Magic Bullet’,” Hermans et al., American Heart Journal, 122: 171-187 (July 1991).

In the pathogenesis of restenosis excessive cell proliferation and migration occurs as a result of growth factors produced by cellular constituents in the blood and the damaged arterial vessel wall which mediate the proliferation of smooth muscle cells in vascular restenosis.

Agents that inhibit the proliferation and/or migration of smooth aortal muscle cells are useful in the treatment and prevention of restenosis. The present invention provides for the use of compounds as smooth aortal muscle cell proliferation inhibitors and, thus inhibitors of restenosis.

SUMMARY OF THE INVENTION

The present invention relates to compounds of formula

wherein

R₁ and R₂ are optionally H, OH, halo, OPO(Oalkyl)₂, OPO(Oaryl)₂, OPO(alkyl)₂, OPO(aryl)₂, or OPO₃ ⁻²; wherein not more than one of R₁ and R₂ may be H, OH or halo;

R₃ and R₄ are optionally CO(CH₂)₃,CO(CH₂)₄, alkyl, or R₃ and R₄ combine to form, with the nitrogen to which they are attached, piperidine, morpholine, pyrollidine, 3-methylpyrollidine, 3,3-dimethylpyrollidine, 3,4-dimethylpyrollidine, azepine, or pipecoline; and pharmaceutically acceptable salts thereof.

The present invention further relates to pharmaceutical compositions containing compounds of formula I, optionally containing estrogen or progestin, and the use of such compounds, alone, or in combination with estrogen or progestin, for alleviating the symptoms of post-menopausal syndrome, particularly osteoporosis, cardiovascular related pathological conditions, and estrogen-dependent cancer. As used herein, the term “estrogen” includes steroidal compounds having estrogenic activity such as, for example, 17β-estradiol, estrone, conjugated estrogen (Premarin®), equine estrogen, 17β-ethynyl estradiol, and the like. As used herein, the term “progestin” includes compounds having progestational activity such as, for example, progesterone, norethylnodrel, norgestrel, megestrol acetate, norethindrone, and the like.

The compounds of the present invention also are useful for inhibiting uterine fibroid disease and endometriosis in women and aortal smooth muscle cell proliferation, particularly restenosis, in humans.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the present invention includes compounds of formula I

wherein

R₁ and R₂ are optionally H, OH, halo, OPO(Oalkyl)₂, OPO(Oaryl)₂, OPO(alkyl)₂, OPO(aryl)₂, or OPO₃ ⁻² ; wherein not more than one of R₁ and R₂ may be H, OH or halo;

R₃ and R₄ are optionally CO(CH₂)₃,CO(CH₂)₄, alkyl, or R₃ and R₄ combine to form, with the nitrogen to which they are attached, piperidine, morpholine, pyrollidine, 3-methylpyrollidine, 3,3-dimethylpyrollidine, 3,4-dimethylpyrollidine, azepine, or pipecoline; and pharmaceutically acceptable salts thereof.

General terms used in the description of compounds herein described bear their usual meanings. For example, “alkyl” refers to straight or branched aliphatic chains of 1 to 6 carbon atoms including methyl, ethyl, propyl, isopropyl, butyl, n-butyl, pentyl, isopentyl, hexyl, isohexyl, and the like. The term “aryl” refers to phenyl and phenyl substituted once or twice with alkyl, C₁-C₆ alkoxy, hydroxy, nitro, or halo. “Halo” includes bromo, chloro, iodo and fluoro.

The compounds of the present invention can be made according to established procedures, such as those detailed in U.S. Pat. Nos. 4,133,814 and 4,418,068, both of which are incorporated by reference herein. Examples of the preparation of analogous compounds are provided in the U.S. Patents discussed above. In general, the process starts with a benzo[b]thiophene having a 6-hydroxyl group and a 2-(4-hydroxyphenyl) group. The starting compound is protected, phosphorylated, and optionally deprotected to form the formula I compounds. Further formula I compounds may then be formed as desired. Specific preparations of compounds of the present invention are described below. Modifications to the above methods may be necessary to accommodate reactive functionalities of particular substituents. Such modifications would be both apparent to, and readily ascertained by, those skilled in the art. The following Scheme illustrate's the preparation of compounds of formula I.

The process in the Scheme 1 is carried out under substantially anhydrous conditions which represents reaction conditions which are virtually free from water. Accordingly, solvents are dried prior to use in the process. Suitable organic solvents include methylene chloride, chloroform, methyl alcohol, toluene, and di or trichloroethane, tetrahydrofruan (THF), dimethylpropylene urea (DMPU), hexamethylphosphoric triamide (HMPA), dimethyl acetamide, tetrahydropyran, dioxane, acetonitrile, diethyl ether, dimethylacetamide, dimethylsulfoxide, dimethoxyethane, dimethylpropylene urea (DMPU), and mixtures thereof.

In preparing a di-4′,6-substituted compound of formula 1, the R groups may both be hydrogen. This compound is then mixed with a phosphourous precursor. The phosphorous precursor is one of the formula LPO(Oalkyl)₂, LPO(Oaryl)₂, LPO(Alkyl)₂, or LPO(aryl)₂. A preferred leaving group (L) is chloro. All of the phosphorous precursors may be made by conventional means. Thereafter, a strong base such as sodium hydride is added to deprotonate the hydroxy groups, resulting in a di-4′,6-substituted compound of formula I. Also, the steps may be done in reverse order.

Alternatively, compounds of formula A may be reacted with PL₃, and subsequently treated with the appropriate nucleophile, such as alcohol (ROH), phenol (ArOH) or an organometallic reagent (RMgX,RLi, etc.) to provide a phosphite intermediate. Oxidation with a peroxide (H₂O₂) results in a 4′,6-disubstituted compound of formula I.

Optionally, for compounds, of formula I in which the R₁ and R₂ groups are OPO(alkyl)₂, the alkyl groups can be removed under acidic conditions (HCl, HBr, etc.) or by employing reagents such as trimethylsilylbromide, to provide the corresponding phosphate (OPO₃ ⁻²).

In order to substitute with different groups of R₁ and R₂, one of the positions is protected with a hydroxy protecting group. The term “hydroxy-protecting group” refers to readily cleavable groups bonded to hydroxy groups, such as the tetrahydropyranyl, 2-methoxyprop-2-yl, 1-ethoxyeth-1-yl, methoxymethyl, β-methoxyethoxymethyl, methylthiomethyl, t-butyl, t-amyl, trityl, 4-methoxytrityl, 4,4′-dimethoxytrityl, 4,4′,4″-trimethoxytrityl, benzyl, allyl, trimethylsilyl, (t-butyldimethylsilyl, and 2,2,2-trichloroethoxycarbonyl groups, and the like. For example, treatment of compound A with one equivalent of t-butyldimethylsilyl chloride and an appropriate amount of base results in a statistical mixture of 4′- and 6-silyl protected phenols which can then be separated by chromatography.

The species of hydroxy-protecting groups is not critical so long as the derivatized hydroxyl group is stable to the conditions of subsequent reaction(s) and can be removed at the appropriate point without disrupting the remainder of the reaction.

Further examples of hydroxy-protecting groups are described by C. B. Reese and E. Haslam, “Protective Groups in Organic Chemistry”, J. G. W. McOmie, Ed., Plenum Press, New York, N.Y., 1973, Chapters 3 and 4, respectively, and T. W. Greene, “Protective Groups in Organic Synthesis”, John Wiley and Sons, New York, N.Y., 1981, Chapters 2 and 3. The monohydroxy-protected compound is then subjected to the reaction conditions as described previously. Thereafter, the protected hydroxy is de-protected and a different substituent may be placed thereon.

Although the free-base form of formula I compounds can be used in the methods of the present invention, it is preferred to prepare and use a pharmaceutically acceptable salt form. Thus, the compounds used in the methods of this invention primarily form pharmaceutically acceptable acid addition salts with a wide variety of organic and inorganic acids, and include the physiologically acceptable salts which are often used in pharmaceutical chemistry. Such salts are also part of this invention. Typical inorganic acids used to form such salts include hydrochloric, hydrobromic, hydroiodic, nitric, sulfuric, phosphoric, hypophosphoric, and the like. Salts derived from organic acids, such as aliphatic mono and dicarboxylic acids, phenyl substituted alkanoic acids, hydroxyalkanoic and hydroxyalkandioic acids, aromatic acids, aliphatic and aromatic sulfonic acids, may also be used. Such pharmaceutically acceptable salts thus include acetate, phenylacetate, trifluoroacetate, acrylate, ascorbate, benzoate, chlorobenzoate, dinitrobenzoate, hydroxybenzoate, methoxybenzoate, methylbenzoate, o-acetoxybenzoate, naphthalene-2-benzoate, bromide, isobutyrate, phenylbutyrate, β-hydroxybutyrate, butyne-1,4-dioate, hexyne-1,4-dioate, caprate, caprylate, chloride, cinnamate, citrate, formate, fumarate, glycollate, heptanoate, hippurate, lactate, malate, maleate, hydroxymaleate, malonate, mandelate, mesylate, nicotinate, isonicotinate, nitrate, oxalate, phthalate, terephthalate, phosphate, monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate, propiolate, propionate, phenylpropionate, salicylate, sebacate, succinate, suberate, sulfate, bisulfate, pyrosulfate, sulfite, bisulfite, sulfonate, benzenesulfonate, p-bromophenylsulfonate, chlorobenzenesulfonate, ethanesulfonate, 2-hydroxyethanesulfonate, methanesulfonate, naphthalene-1-sulfonate, naphthalene-2-sulfonate, p-toluenesulfonate, xylenesulfonate, tartarate, and the like. A preferred salt is the hydrochloride salt.

The pharmaceutically acceptable acid addition salts are typically formed by reacting a compound of formula I with an equimolar or excess amount of acid. The reactants are generally combined in a mutual solvent such as diethyl ether or ethyl acetate. The salt normally precipitates out of solution within about one hour to 10 days and can be isolated by filtration or the solvent can be stripped off by conventional means.

The pharmaceutically acceptable salts generally have enhanced solubility characteristics compared to the compound from which they are derived, and thus are often more amenable to formulation as liquids or emulsions.

The following examples are presented to further illustrate the preparation of compounds of the present invention. It is not intended that the invention be limited in scope by reason of any of the following examples.

NMR data for the following Examples were generated on a GE 300 MHz NMR instrument, and anhydrous d-6 DMSO was used as the solvent unless otherwise indicated.

Preparation 1 Raloxifene 6-hydroxy-2-(4-hydroxyphenyl)-3-[4-(2-piperidinoethoxy)benzoyl]benzo[b]thiophene, hydrochloride

Under a nitrogen blanket, a mixture of 3 g. of 4-(2-piperidinoethoxy)benzoic acid, hydrochloride, 2 drops of dimethylformamide, 2.5 ml. of thionyl chloride and 40 ml. of chlorobenzene was heated at 70°-75° C. for about one hour. The excess thionyl chloride and 15-20 ml. of solvent were then distilled off. The remaining suspension was cooled to ambient temperature, and to it were added 100 ml. of dichloromethane, 2.7 g. of 6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene and 10 g. of aluminum chloride. The solution was stirred for about one hour. 7.5 ml of ethanethiol was added, and the mixture was stirred for 45 minutes more. Then 40 ml. of tetrahydrofuran was added, followed by 15 ml. of 20% hydrochloric acid, with an exotherm to reflux. Fifty ml. of water and 25 ml. of saturated aqueous sodium chloride was added. The mixture was stirred and allowed to cool to ambient temperature. The precipitate was collected by filtration and washed successively with 30 ml. of water, 40 ml. of 25% aqueous tetrahydrofuran, and 35 ml. of water. The solids were then dried at 40° C. under vacuum to obtain 5.05 g. of product, which was identified by nmr.

δ1.7 (6H. m. N)CH₂CH₂)₂CH₂); 2.6-3.1 (2H, m, NCH₂); 3.5-4.1 (4H, m, NCH₂); 4.4 (2H, m, OCH₂); 6.6-7.4 (9H, m, aromatic); 7.7(2H, d, aromatic o to CO); 9.8(2H, m, OH).

Experimental EXAMPLE 1

To a solution of raloxifene (2.0 g, 3.92 mmol) stirring in dimethylpropyleneurea (40 mL) at room temperature was added sodium hydride (0.63 g of a 60% dispersion in mineral oil, 16 mmol). After 1 h, (EtO)₂POCl (1.45 mL, 10 mmol) was added to the deep red solution and the mixture subsequently stirred for 1 h then carefully quenched with water. The mixture was extracted with ethyl acetate and the combined organic extracts washed with brine, dried (sodium sulfate), filtered, and concentrated. Purification by radial chromatography (silica gel, 10% methanol in ethyl acetate) gave 1.12 g of the desired product as yellow oil which was taken up in THF, acidified with 1.5N HCl, and concentrated to the pictured product as white foam:

1H NMR (300 MHz) δ8.02 (s, 1H), 7.70 (d, J=8.8, 2H), 7.45 (m, 3H), 7.27 (m, 1H), 7.17 (d, J=8.2 Hz, 2H), 6.96 (d, J=8.8 Hz, 2H), 4.41 (br s, 2 H), 4.10 (m, 8H), 3.40 (m, 4H), 2.93 (m, 2H), 1.80 (m,5H), 1.21 (m, 13H); (MS(FD) m/z 747 (M+)).

EXAMPLE 2

In a manner similar to the preparation in Example 1, reaction of raloxifene (1.5 g, 2.94 mmol), sodium hydride (0.47 g, 12 mmol), and (PhO)₂POCl (1.53 mL, 7.35 mmol) followed by acidification gave the pictured product as a white foam: ¹H-NMR (300 MHz, DMSO-d₆) 8.21 (s, 1H), 7.78 (d, J=8.6 Hz, 2H), 7.2-7.6 (series of m, 26 H), 7.02 (d, J=8.8 Hz, 2H), 4.50 (m, 2H), 3.42 (m, 4H), 3.95 (m, 2H), 1.75 (m, 5H), 1.37 (m, 1H); MS (FAB) 938 (M+−HCl).

EXAMPLE 3

In a manner similar to the preparation of Example 1, reaction of raloxifene (2.0 g, 3.92 mmol), sodium hydride (0.63 g, 16 mmol), and Ph₂POCl (1.90 mL, 10.0 mmol) followed by acidification gave the pictured product as a white foam: ¹H-NMR (300 MH₂)8.13 (s, 1H), 7.20-7.99 (series of m, 28H), 6.96 (d, J=8.5 Hz, 2H), 4.51 (m, 2H), 3.49 (m, 4H), 2.95 (m, 2H), 1.80 (m, 5H), 1.38 (m, 1H); MS (FD) m/ z 874 (M+).

Test Procedure General Preparation Procedure

In the examples illustrating the methods, a post-menopausal model was used in which effects of different treatments upon circulating lipids were determined.

Seventy-five day old female Sprague Dawley rats (weight range of 200 to 225g) were obtained from Charles River Laboratories (Portage, Mich.). The animals were either bilaterally ovariectomized (OVX) or exposed to a Sham surgical procedure at Charles River Laboratories, and then shipped after one week. Upon arrival, they were housed in metal hanging cages in groups of 3 or 4 per cage and had ad libitum access to food (calcium content approximately 0.5%) and water for one week. Room temperature was maintained at 22.20°±1.7° C. with a minimum relative humidity of 40%. The photoperiod in the room was 12 hours light and 12 hours dark.

Dosing Regimen Tissue Collection. After a one week acclimation period (therefore, two weeks post-OVX) daily dosing with test compound was initiated. 17α-ethynyl estradiol or the test compound were given orally, unless otherwise stated, as a suspension in 1% carboxymethylcellulose or dissolved in 20% cyclodextrin. Animals were dosed daily for 4 days. Following the dosing regimen, animals were weighed and anesthetized with a ketamine: xylazine (2:1, V:V) mixture and a blood sample was collected by cardiac puncture. The animals were then sacrificed by asphyxiation with CO₂, the uterus was removed through a midline incision, and a wet uterine weight was determined.

Cholesterol Analysis. Blood samples were allowed to clot at room temperature for 2 hours, and serum was obtained following centrifugation for 10 minutes at 3000 rpm. Serum cholesterol was determined using a Boehringer Mannheim Diagnostics high performance cholesterol assay. Briefly the cholesterol was oxidized to cholest-4-en-3-one and hydrogen peroxide. The hydrogen peroxide was then reacted with phenol and 4-aminophenazone in the presence of peroxidase to produce a p-quinone imine dye, which was read spectrophotemetrically at 500 nm. Cholesterol concentration was then calculated against a standard curve. The entire assay was automated using a Biomek Automated Workstation.

Uterine Eosinophil Peroxidase (EPO) Assay. Uteri were kept at 4° C. until time of enzymatic analysis. The uteri were then homogenized in 50 volumes of 50 mM Tris buffer (pH—8.0) containing 0.005% Triton X-100. Upon addition of 0.01% hydrogen peroxide and 10 mM O-phenylenediamine (final concentrations) in Tris buffer, increase in absorbance was monitored for one minute at 450 nm. The presence of eosonophils in the uterus is an indication of estrogenic activity of a compound. The maximal velocity of a 15 second interval was determined over the initial, linear portion of the reaction curve.

Source of Compound: 17α-ethynyl estradiol was obtained from Sigma chemical Co., St. Louis, Mo.

Influence of Formula I Compounds on Serum Cholesterol and Determination of Activity

Data presented in Table 1 below show comparative results among ovariectomized rats, rats treated with 17α-ethynyl estradiol (EE₂; an orally available form of estrogen), and rats treated with certain compounds of the present invention. Although EE₂ caused a decrease in serum cholesterol when orally administered at 0.1 mg/kg/day, it also exerted a stimulatory action on the uterus so that EE₂ uterine weight was substantially greater than the uterine weight of ovariectomized test animals. This uterine response to estrogen is well recognized in the art.

Not only did the compounds of the present invention generally reduce serum cholesterol compared to the ovariectomized control animals, but uterine weight was only minimally increased to slightly decreased with the majority of the formula compounds tested. Compared to estrogenic compounds known in the art, the benefit of serum cholesterol reduction without adversely affecting uterine weight is quite rare and desirable.

As is expressed in the below data, estrogenicity also was assessed by evaluating the adverse response of eosinophil infiltration into the uterus. The compounds of the present invention did not cause any increase in the number of eosinophils observed in the stromal layer of ovariectomized rats, while estradiol cause a substantial, expected increase in eosinophil infiltration.

The data presented in the Tables 1 below reflects the response per treatment.

TABLE 1 Uterine Weight Uterine Serum Cholesterol Dose (% increase EPO (% decrease Compound mg/kg vs. OVX) (V. max) vs. OVX) EE₂ 0.1 171.5 109.3 85.9 Raloxifene 0.01 44.2 2.2 65 0.1 55.5 4.3 75.6 1.0 50.3 3.9 71.1 Example 1 0.01 51.5 0.68 24.3 0.1 25.2 6.5 41.1 1.0 37.0 5.8 17.4 Example 2 0.01 17.4 4 −48.2 0.1 12.4 9.8 15.6 1.0 31.4 5.6 55.2 Example 3 0.01 22.5 3.7 −25 0.1 47.1 7 37.6 1.0 24.7 6.7 57.5

In addition to the demonstrated benefits of the compounds of the present invention, especially when compared to estradiol, the above data clearly demonstrate that compounds of Formula I are not estrogen mimetics. Furthermore, no deleterious toxicological effects (survival) were observed with any treatment.

Osteoporosis Test Procedure

Following the General Preparation Procedure, infra, the rats are treated daily for 35 days (6 rats per treatment group) and sacrificed by carbon dioxide asphyxiation on the 36th day. The 35 day time period is sufficient to allow maximal reduction in bone density, measured as described herein. At the time of sacrifice, the uteri is removed, dissected free of extraneous tissue, and the fluid contents is expelled before determination of wet weight in order to confirm estrogen deficiency associated with complete ovariectomy. Uterine weight is routinely reduced about 75% in response to ovariectomy. The uteri are then placed in 10% neutral buffered formalin to allow for subsequent histological analysis.

The right femurs are excised and digitilized x-rays generated and analyzed by an image analysis program (NIH image) at the distal metaphysis. The proximal aspect of the tibiae from these animals are also scanned by quantitative computed tomography.

In accordance with the above procedures, compounds of the present invention are orally administered to test animals. A positive impact in the above assay is indicated by an inhibition in bone loss provided by the compounds of formula 1.

MCF-7 Proliferation Assay

MCF-7 breast adenocarcinoma cells (ATCC HTB 22) were maintained in MEM (minimal essential medium, phenol red-free, Sigma, St. Louis, Mo.) supplimented with 10% fetal bovine serum (FBS) (V/V), L-glutamine (2 mM), sodium pyruvate (1 mM), HEPES {(N-[2-hydroxyethyl]piperazine-N′-[2-ethanesulfonic acid]10 mM}, non-essential amino acids and bovine insulin (1 ug/mL) (maintenance medium). Ten days prior to assay, MCF-7 cells were switched to maintenance medium supplemented with 10% dextran coated charcoal stripped fetal bovine serum (DCC-FBS) assay medium) in place of 10% FBS to deplete internal stores of steroids. MCF-7 cells were removed from maintenance flasks using cell dissociation medium (Ca++/Mg++ free HBSS (phenol red-free) supplemented with 10 mM HEPES and 2 mM EDTA). Cells were washed twice with assay medium and adjusted to 80,000 cells/ML. Approximately 100 μL (8,000 cells) were added to flat-bottom microculture wells (Costar 3596) and incubated at 37° C. in a 5% CO₂ humidified incubator for 48 hours to allow for cell adherence and equilibration after transfer. Serial dilutions of drugs or DMSO as a diluent control were prepared in assay medium and 50 μL transferred to triplicate microcultures followed by 50 μL assay medium for a final volume of 200 μL. After an additional 48 hours at 37° C. in a 5% CO₂ humidified incubator, microcultures were pulsed with tritiated thymidine (1 uCi/well) for 4 hours. Cultures were terminated by freezing at −70° C. for 24 hours followed by thawing and harvesting of microcultures using a Skatron Semiautomatic Cell Harvester. Samples were counted by liquid scintillation using a Wallac BetaPlace β counter. Results in Table 2 below show the ED₅₀ for certain compounds of the present invention.

TABLE 2 Compound (Example Reference) IC₅₀ nM 1 1 2 10 3 1

DMBA-Induced Mammary Tumor Inhibition

Estrogen-dependent mammary tumors are produced in female Sprague-Dawley rats which are purchased from Harlan Industries, Indianapolis, Ind. At about 55 days of age, the rats receive a single oral feeding of 20 mg of 7,12-dimethylbenz[a]anthracene (DMBA). About 6 weeks after DMBA administration, the mammary glands are palpated at weekly intervals for the appearance of tumors. Whenever one or more tumors appear, the longest and shortest diameters of each tumor are measured with a metric caliper, the measurements are recorded, and that animal is selected for experimentation. An attempt is made to uniformly distribute the various sizes of tumors in the treated and control groups such that average-sized tumors are equivalently distributed between test groups. Control groups and test groups for each experiment contain 5 to 9 animals.

Compounds of Formula I are administered either through intraperitoneal injections in 2% acacia, or orally. Orally administered compounds are either dissolved or suspended in 0.2 mL corn oil. Each treatment, including acacia and corn oil control treatments, is administered once daily to each test animal. Following the initial tumor measurement and selection of test animals, tumors are measured each week by the above-mentioned method. The treatment and measurements of animals continue for 3 to 5 weeks at which time the final areas of the tumors are determined. For each compound and control treatment, the change in the mean tumor area is determined.

Uterine Fibrosis Test Procedures

Test 1

Between 3 and 20 women having uterine fibrosis are administered a compound of the present invention. The amount of compound administered is from 0.1 to 1000 mg/day, and the period of administration is 3 months.

The women are observed during the period of administration, and up to 3 months after discontinuance of administration, for effects on uterine fibrosis.

Test 2

The same procedure is used as in Test 1, except the period of administration is 6 months.

Test 3

The same procedure is used as in Test 1, except the period of administration is 1 year.

Test 4

A. Induction of Fibroid Tumors in Guinea Pig

Prolonged estrogen stimulation is used to induce leiomyomata in sexually mature female guinea pigs. Animals are dosed with estradiol 3-5 times per week by injection for 2-4 months or until tumors arise. Treatments consisting of a compound of the invention or vehicle is administered daily for 3-16 weeks and then animals are sacrificed and the uteri harvested and analyzed for tumor regression.

B. Implantation of Human Uterine Fibroid Tissue in Nude Mice

Tissue from human leiomyomas are implanted into the peritoneal cavity and or uterine myometrium of sexually mature, castrated, female, nude mice. Exogenous estrogen is supplied to induce growth of the explanted tissue. In some cases, the harvested tumor cells are cultured in vitro prior to implantation. Treatment consisting of a compound of the present invention or vehicle is supplied by gastric lavage on a daily basis for 3-16 weeks and implants are removed and measured for growth or regression. At the time of sacrifice, the uteri is harvested to assess the status of the organ.

Test 5

A. Tissue from Human Uterine Fibroid Tumors is Harvested and Maintained, in vitro, as Primary Nontransformed Cultures

Surgical specimens are pushed through a sterile mesh or sieve, or alternately teased apart from surrounding tissue to produce a single cell suspension. Cells are maintained in media containing 10% serum and antibiotic. Rates of growth in the presence and absence of estrogen are determined. Cells are assayed for their ability to produce complement component C3 and their response to growth factors and growth hormone. In vitro cultures are assessed for their proliferative response following treatment with progestins, GnRH, a compound of the present invention and vehicle. Levels of steroid hormone receptors are assessed weekly to determine whether important cell characteristics are maintained in vitro. Tissue from 5-25 patients are utilized.

Activity in at least one of the above tests indicates the compounds of the present invention are of potential in the treatment of uterine fibrosis.

Endometriosis Test Procedure

In Tests 1 and 2, effects of 14-day and 21-day administration of compounds of the present invention on the growth of explanted endometrial tissue can be examined.

Test 1

Twelve to thirty adult CD strain female rats are used as test animals. They are divided into three groups of equal numbers. The estrous cycle of all animals is monitored. On the day of proestrus, surgery is performed on each female. Females in each group have the left uterine horn removed, sectioned into small squares, and the squares are loosely sutured at various sites adjacent to the mesenteric blood flow. In addition, females in Group 2 have the ovaries removed.

On the day following surgery, animals in Groups 1 and 2 receive intraperitoneal injections of water for 14 days whereas animals in Group 3 receive intraperitoneal injections of 1.0 mg of a compound of the present invention per kilogram of body weight for the same duration. Following 14 days of treatment, each female is sacrificed and the endometrial explants, adrenals, remaining uterus, and ovaries, where applicable, are removed and prepared for histological examination. The ovaries and adrenals are weighed.

Test 2

Twelve to thirty adult CD strain female rats are used as test animals. They are divided into two equal groups. The estrous cycle of all animals is monitored. On the day of proestrus, surgery is performed on each female. Females in each group have the left uterine horn removed, sectioned into small squares, and the squares are loosely sutured at various sites adjacent to the mesenteric blood flow.

Approximately 50 days following surgery, animals assigned to Group 1 receive intraperitoneal injections of water for 21 days whereas animals in Group 2 receive intraperitoneal injections of 1.0 mg of a compound of the present invention per kilogram of body weight for the same duration. Following 21 days of treatment, each female is sacrificed and the endometrial explants and adrenals are removed and weighed. The explants are measured as an indication of growth. Estrous cycles are monitored.

Test 3

A. Surgical Induction of Endometriosis

Autographs of endometrial tissue are used to induce endometriosis in rats and/or rabbits. Female animals at reproductive maturity undergo bilateral oophorectomy, and estrogen is supplied exogenously thus providing a specific and constant level of hormone. Autologous endometrial tissue is implanted in the peritoneum of 5-150 animals and estrogen supplied to induce growth of the explanted tissue. Treatment consisting of a compound of the present invention is supplied by gastric lavage on a daily basis for 3-16 weeks, and implants are removed and measured for growth or regression. At the time of sacrifice, the intact horn of the uterus is harvested to assess status of endometrium.

B. Implantation of Human Endometrial Tissue in Nude Mice

Tissue from human endometrial lesions is implanted into the peritoneum of sexually mature, castrated, female, nude mice. Exogenous estrogen is supplied to induce growth of the explanted tissue. In some cases, the harvested endometrial cells are cultured in vitro prior to implantation. Treatment consisting of a compound of the present invention supplied by gastric lavage on a daily basis for 3-16 weeks, and implants are removed and measured for growth or regression. At the time of sacrifice, the uteri is harvested to assess the status of the intact endometrium.

Test 4

A. Tissue from Human Endometrial Lesions is Harvested and Maintained in vitro as Primary Nontransformed Cultures

Surgical specimens are pushed through a sterile mesh or sieve, or alternately teased apart from surrounding tissue to produce a single cell suspension. Cells are maintained in media containing 10% serum and antibiotic. Rates of growth in the presence and absence of estrogen are determined. Cells are assayed for their ability to produce complement component C3 and their response to growth factors and growth hormone. In vitro cultures are assessed for their proliferative response following treatment with progestins, GnRH, a compound of the invention, and vehicle. Levels of steroid hormone receptors are assessed weekly to determine whether important cell characteristics are maintained in vitro. Tissue from 5-25 patients is utilized.

Activity in any of the above assays indicates that the compounds of the present invention are useful in the treatment of endometriosis.

Inhibition of Aortal Smooth Cell Proliferation/Restenosis Test Procedure

Compounds of the present invention have capacity to inhibit aortal smooth cell proliferation. This can be demonstrated by using cultured smooth cells derived from rabbit aorta, proliferation being determined by the measurement of DNA synthesis. Cells are obtained by explant method as described in Ross, J. of Cell Bio. 50: 172 (1971). Cells are plated in 96 well microtiter plates for five days. The cultures become confluent and growth arrested. The cells are then transferred to Dulbecco's Modified Eagle's Medium (DMEM) containing 0.5-2% platelet poor plasma, 2 mM L-glutamine, 100 U/ml penicillin, 100 mg ml streptomycin, 1 mC/ml ³H-thymidine, 20 ng/ml platelet-derived growth factor, and varying concentrations of the present compounds. Stock solution of the compounds is prepared in dimethyl sulphoxide and then diluted to appropriate concentration (0.01-30 mM) in the above assay medium. Cells are then incubated at 37° C. for 24 hours under 5% CO₂/95% air. At the end of 24 hours, the cells are fixed in methanol. ³H thymidine incorporation in DNA is then determined by scintillation counting as described in Bonin, et al., Exp. Cell Res. 181: 475-482 (1989).

Inhibition of aortal smooth muscle cell proliferation by the compounds of the present invention are further demonstrated by determining their effects on exponentially growing cells. Smooth muscle cells from rabbit aortae are seeded in 12 well tissue culture plates in DMEM containing 10% fetal bovine serum, 2 mM L-glutamine, 100 U/ml penicillin, and 100 mg/ml streptomycin. After 24 hours, the cells are attached and the medium is replaced with DMEM containing 10% serum, 2 mM L-glutamine, 100 U/ml penicillin, 100 mg/ml streptomycin, and desired concentrations of the compounds. Cells are allowed to grow for four days. Cells are treated with trypsin and the number of cells in each culture is determined by counting using a ZM-Coulter counter.

Activity in the above tests indicates that the compounds of the present invention are of potential in the treatment of restenosis.

The present invention also provides a method of alleviating post-menopausal syndrome in women which comprises the aforementioned method using compounds of Formula I and further comprises administering to a woman an effective amount of estrogen or progestin. These treatments are particularly useful for treating osteoporosis and lowering serum cholesterol because the patient will receive the benefits of each pharmaceutical agent while the compounds of the present invention would inhibit undesirable side-effects of estrogen and progestin. Activity of these combination treatments in any of the post-menopausal tests, infra, indicates that the combination treatments are useful for alleviating the symptoms of post-menopausal symptoms in women.

Various forms of estrogen and progestin are commercially available. Estrogen-based agents include, for example, ethynyl estrogen (0.01-0.03 mg/day), mestranol (0.05-0.15 mg/day), and conjugated estrogenic hormones such as Premarin® (Wyeth-Ayerst; 0.3-2.5 mg/day). Progestin-based agents include, for example, medroxyprogesterone such as Provera® (Upjohn; 2.5-10 mg/day), norethylnodrel (1.0-10.0 mg/day), and nonethindrone (0.5-2.0 mg/day). A preferred estrogen-based compound is Premarin, and norethylnodrel and norethindrone are preferred progestin-based agents.

The method of administration of each estrogen- and progestin-based agent is consistent with that which is known in the art. For the majority of the methods of the present invention, compounds of Formula I are administered continuously, from 1 to 3 times daily. However, cyclical therapy may especially be useful in the treatment of endometriosis or may be used acutely during painful attacks of the disease. In the case of restenosis, therapy may be limited to short (1-6 months) intervals following medical procedures such as angioplasty.

As used herein, the term “effective amount” means an amount of compound of the present invention which is capable of alleviating the symptoms of the various pathological conditions herein described. The specific dose of a compound administered according to this invention will, of course, be determined by the particular circumstances surrounding the case including, for example, the compound administered, the route of administration, the state of being of the patient, and the pathological condition being treated. A typical daily dose will contain a nontoxic dosage level of from about 5 mg to about 600 mg/day of a compound of the present invention. Preferred daily doses generally will be from about 15 mg to about 80 mg/day.

The compounds of this invention can be administered by a variety of routes including oral, rectal, transdermal, subucutaneus, intravenous, intramuscular, and intranasal. These compounds preferably are formulated prior to administration, the selection of which will be decided by the attending physician. Thus, another aspect of the present invention is a pharmaceutical composition comprising an effective amount of a compound of Formula I, or a pharmaceutically acceptable salt thereof, optionally containing an effective amount of estrogen or progestin, and a pharmaceutically acceptable carrier, diluent, or excipient.

The total active ingredients in such formulations comprises from 0.1% to 99.9% by weight of the formulation. By “pharmaceutically acceptable” it is meant the carrier, diluent, excipients and salt must be compatible with the other ingredients of the formulation, and not deleterious to the recipient thereof.

Pharmaceutical formulations of the present invention can be prepared by procedures known in the art using well known and readily available ingredients. For example, the compounds of formula I, with or without an estrogen or progestin compound, can be formulated with common excipients, diluents, or carriers, and formed into tablets, capsules, suspensions, powders, and the like. Examples of excipients, diluents, and carriers that are suitable for such formulations include the following: fillers and extenders such as starch, sugars, mannitol, and silicic derivatives; binding agents such as carboxymethyl cellulose and other cellulose derivatives, alginates, gelatin, and polyvinylpyrrolidone; moisturizing agents such as glycerol; disintegrating agents such as calcium carbonate and sodium bicarbonate; agents for retarding dissolution such as paraffin; resorption accelerators such as quaternary ammonium compounds; surface active agents such as cetyl alcohol, glycerol monostearate; adsorptive carriers such as kaolin and bentonite; and lubricants such as talc, calcium and magnesium stearate, and solid polyethyl glycols.

The compounds also can be formulated as elixirs or solutions for convenient oral administration or as solutions appropriate for parenteral administration, for example, by intramuscular, subcutaneous or intravenous routes. Additionally, the compounds are well suited to formulation as sustained release dosage forms and the like. The formulations can be so constituted that they release the active ingredient only or preferably in a particular physiological location, possibly over a period of time. The coatings, envelopes, and protective matrices may be made, for example, from polymeric substances or waxes.

Compounds of formula I, alone or in combination with a pharmaceutical agent of the present invention, generally will be administered in a convenient formulation. The following formulation examples only are illustrative and are not intended to limit the scope of the present invention.

Formulations

In the formulations which follow, “active ingredient” means a compound of formula I, or a salt or solvate thereof.

Formulation 1: Gelatin Capsules Hard gelatin capsules are prepared using the following: Ingredient Quantity (mg/capsule) Active ingredient 0.1-1000 Starch, NF 0-650 Starch flowable powder 0-650 Silicone fluid 350 centistokes 0-15 

The formulation above may be changed in compliance with the reasonable variations provided.

A tablet formulation is prepared using the ingredients below:

Formulation 2: Tablets Ingredient Quantity (mg/tablet) Active ingredient  2.5-1000 Cellulose, microcrystalline 200-650  Silicon dioxide, fumed 10-650 Stearate acid 5-15

The components are blended and compressed to form tablets.

Alternatively, tablets each containing 2.5-1000 mg of active ingredient are made up as follows:

Formulation 3: Tablets Ingredient Quantity (mg/tablet) Active ingredient 25-1000 Starch 45 Cellulose, microcrystalline 35 Polyvinylpyrrolidone 4 (as 10% solution in water) Sodium carboxymethyl cellulose 4.5 Magnesium stearate 0.5 Talc 1

The active ingredient, starch, and cellulose are passed through a No. 45 mesh U.S. sieve and mixed thoroughly. The solution of polyvinylpyrrolidone is mixed with the resultant powders which are then passed through a No. 14 mesh U.S. sieve. The granules so produced are dried at 50°-60° C. and passed through a No. 18 mesh U.S. sieve. The sodium carboxymethyl starch, magnesium stearate, and talc, previously passed through a No. 60 U.S. sieve, are then added to the granules which, after mixing, are compressed on a tablet machine to yield tablets.

Suspensions each containing 0.1-1000 mg of medicament per 5 ml dose are made as follows:

Formulation 4: Suspensions Ingredient Quantity (mg/5 ml) Active ingredient 0.1-1000 mg Sodium carboxymethyl cellulose 50 mg Syrup 1.25 mg Benzoic acid solution 0.10 mL Flavor q.v. Color q.v. Purified water to 5 mL

The medicament is passed through a No. 45 mesh U.S. sieve and mixed with the sodium carboxymethyl cellulose and syrup to form a smooth paste. The benzoic acid solution, flavor, and color are diluted with some of the water and added, with stirring. Sufficient water is then added to produce the required volume.

An aerosol solution is prepared containing the following ingredients:

Formulation 5: Aerosol Ingredient Quantity (% by weight) Active ingredient 0.25 Ethanol 25.75 Propellant 22 (Chlorodifluoromethane) 70.00

The active ingredient is mixed with ethanol and the mixture added to a portion of the propellant 22, cooled to 30° C., and transferred to a filling device. The required amount is then fed to a stainless steel container and diluted with the remaining propellant. The valve units are then fitted to the container.

Suppositories are prepared as follows:

Formulation 6: Suppositories Ingredient Quantity (mg/suppository) Active ingredient 250 Saturated fatty acid glycerides 2,000

The active ingredient is passed through a No. 60 mesh U.S. sieve and suspended in the saturated fatty acid glycerides previously melted using the minimal necessary heat. The mixture is then poured into a suppository mold of nominal 2 g capacity and allowed to cool.

An intravenous formulation is prepared as follows:

Formulation 7: Intravenous Solution Ingredient Quantity Active ingredient 50 mg Isotonic saline 1,000 mL

The solution of the above ingredients is intravenously administered to a patient at a rate of about 1 mL per minute.

Formulation 8: Combination Capsule I Ingredient Quantity (mg/capsule) Active ingredient 50 Premarin 1 Avicel pH 101 50 Starch 1500 117.50 Silicon Oil 2 Tween 80 0.50 Cab-O-Sil 0.25

Formulation 9: Combination Capsule II Ingredient Quantity (mg/capsule) Active ingredient 50 Norethylnodrel 5 Avicel pH 101 82.50 Starch 1500 90 Silicon Oil 2 Tween 80 0.50

Formulation 10: Combination Tablet Ingredient Quantity (mg/capsule) Active ingredient 50 premarin 1 Corn Starch NF 50 Povidone, K29-32 6 Avicel pH 101 41.50 Avicel pH 102 136.50 Crospovidone XL10 2.50 Magnesium Stearate 0.50 Cab-O-Sil 0.50 

We claim:
 1. A compound of the formula I

wherein R¹ and R² are optionally H, OH, halo, OPO(Oalkyl)₂, OPO(alkyl)₂, OPO(aryl)₂, or OPO₃ ⁻²; wherein not more than one of R¹ and R² may be H, OH or halo; R³ and R⁴ are optionally CO(CH₂)₂CH₃, CO(CH₂)₃CH₃, alkyl, or R³ and R⁴ combine to form, with the nitrogen to which they are attached, piperidine, morpholine, pyrollidine, 3-methylpyrollidine, 3,3-dimethylpyrollidine, 3,4-dimethylpyrollidine, azepine, or pipecoline; and pharmaceutically acceptable salts thereof.
 2. A compound according to claim 1 wherein R¹ and R² are both —OPO(Oethyl)₂ or OPO(phenyl)₂.
 3. A pharmaceutical composition comprising a compound according to claim 1 in combination with a pharmaceutically acceptable carrier, diluent or excipient. 